Note: This monograph focuses on beta-sitosterol. Beta-sitosterol is a plant sterol. Thus there may be theoretical uses, safety issues, adverse effects, interactions, and mechanisms of action associated with plant sterols that are not specifically addressed in this monograph.

Beta-sitosterol is one of the most common dietary phytosterols (plant sterols) found in and made exclusively by plants. Other phytosterols include campesterol and stigmasterol. Stanols are saturated derivatives of sterols.

Beta-sitosterol is the main sterol in the Western diet. Some evidence suggests that Americans consume about 165 milligrams of beta-sitosterol daily. Beta-sitosterol is found in the tissue, plasma, and feces of healthy individuals.

Beta-sitosterol is found in plant-based foods, such as fruits, vegetables, soybeans, breads, peanuts, and peanut products. Beta-sitosterol is also present in bourbon and oils, such as olive, flaxseed, and tuna. Plant oils contain the highest concentration of phytosterols. Nuts and seeds contain moderate amounts of phytosterols, while fruits and vegetables generally contain the lowest phytosterol concentrations. For example, roasted peanuts contain 61-114 milligrams per 100 grams, 78-83% of which is in the form of beta-sitosterol. Peanut butter contains 144-157 milligrams per 100 grams. These values indicate that peanut products are a good source of phytosterols, specifically, beta-sitosterol. Avocados have also been identified as a good source of beta-sitosterol. Beta-sitosterol can also be derived from pulp and paper mill effluents.

Margarines enriched with phytosterol esters, including beta-sitosterol, have been marketed for their cholesterol-lowering effects. Sitosterols are also used in products for the treatment of other medical conditions, including, but not limited to, benign prostatic hyperplasia (enlarged prostate) and enhancing the immune system.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Beta-sitosterol and beta-sitosterol glucoside have been used to treat symptoms of BPH (enlarged prostate). Several studies support this use, although further research is needed to draw conclusions.

B

Due to limited research, it is unclear if beta-sitosterol helps with male-pattern baldness. Further research is needed.

C

Research has shown that a mixture containing a combination of sesame oil, beta-sitosterol, berberine, and other plant ingredients helped heal burns. The effect of beta-sitosterol alone is unclear and further studies are needed.

C

Evidence has demonstrated that supplementation of plant sterols, including beta-sitosterol, decreases total cholesterol and LDL-C (low density lipoprotein cholesterol, or "bad cholesterol"). However, research of beta-sitosterol alone is needed to draw conclusions.

C

Due to the potential immune-boosting effects of beta-sitosterol and beta-sitosterol glucoside, they have been studied as a treatment for HIV. However, more research is needed before a conclusion can be made.

C

Beta-sitosterol has been used to enhance the immune system after intense exercise. More research is needed to draw firm conclusions.

C

It is unclear if beta-sitosterol and beta-sitosterol glucoside is beneficial for rheumatoid arthritis. Further research is needed to draw conclusions.

C

Beta-sitosterol and beta-sitosterol glucoside have been studied for the treatment of tuberculosis in combination with standard therapy. It is unclear of beta-sitosterol is beneficial for tuberculosis. Further research is needed before a conclusion can be made.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

For benign prostatic hypertrophy, 90-130 milligrams beta-sitosterol has been taken by mouth daily in 1-3 doses daily for six months.

For HIV, one capsule (20 milligrams beta-sitosterol and 0.2 milligrams beta-sitosterol glucoside) has been taken by mouth daily for 39 months.

For high cholesterol, 1-8 grams of beta-sitosterol has been taken by mouth 1-3 times daily for up to three months.

For enhancing the immune system, one capsule (20 milligrams beta-sitosterol and 0.2 milligrams beta-sitosterol glucoside) has been taken by mouth three times daily for four weeks before a marathon.

For rheumatoid arthritis, one capsule (20 milligrams beta-sitosterol and 0.2 milligrams beta-sitosterol glucoside) has been taken by mouth three times daily for 24 weeks.

Children (under 18 years old)

For high cholesterol, 12 grams beta-sitosterol has been taken by mouth in three divided doses daily for three months.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in individuals with known allergy to beta-sitosterol or beta-sitosterol glucoside.

Some brands of sitosterol are made from a natural pine source and therefore may have possible cross-sensitivity in people allergic to pine.

Side Effects and Warnings

Beta-sitosterol is likely safe when taken by mouth in recommended doses for up to six months for enlarged prostate or for lowering cholesterol levels.

Beta-sitosterol may lower blood sugar levels. Caution is advised in patients with diabetes or low blood sugar levels and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Beta-sitosterol may increase the risk of bleeding. Caution is advised in patients with bleeding disorders or those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Use cautiously in individuals with asthma, breathing disorders, or stomach problems.

Beta-sitosterol may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Beta-sitosterol may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Beta-sitosterol may have blood sugar-lowering effects and interact with antidiabetic herbs or supplements.

Beta-sitosterol may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.